1. Field of the Invention
The present invention relates to a method and device for opening and closing a door of a drawer-type cooking device including a cooking device body having a heating chamber, a drawer body movably disposed such that the drawer body can be drawn out from the heating chamber of the cooking device body to the outside, and a drive mechanism for driving the drawer body in the draw-out and push-in directions via a transmission mechanism.
2. Description of the Related Art
In the related art, there has been proposed a cooking device comprising an apparatus body having a cooking chamber in which an object to be cooked is housed, a door for shielding the cooking chamber from outside, a bottom plate moving in conjunction with the door, a sliding mechanism for sliding the bottom plate out of/in the cooking chamber, a motor for driving the bottom plate, transmission means for transmitting a drive force of the motor to the bottom plate, a latch device for opening and retaining the door, a door open/close switch, and a control circuit for controlling drive of the motor so as to operate the door upon reception of a signal from the door open/close switch (Japanese Patent Laid-Open Publication No. 3-45820 (Patent Document 1)). The bottom plate is directly coupled to the lower portion of the door in the vicinity of the lower hem. When the door is opened, the sides of the bottom plate are in an open state.
Also, there has been proposed a cooking device in which a slide body in which an object to be heated is housed is slidably provided in a cooking device body, comprising detecting means for detecting that the slide body has been slid out, control means for outputting an excitation command signal when receiving a detection signal from the detecting means, and an electromagnet leg portion disposed on the bottom face of the cooking device body and excited when receiving the excitation command signal (Japanese Patent Laid-Open Publication No. 6-109257 (Patent Document 2)). When the slide body is slid out, the excitation command signal is output from the control means based on detection by the detecting means, and the electromagnet leg portion disposed on the bottom face of the cooking device body is excited. The electromagnet leg portion is chucked to a metallic placing face to prevent the cooking device from being turned over, so as to use the cooking device in a stable state all the time.
Also, there has been proposed an microwave oven, wherein a heating container having an opening in its top is provided so as to be freely drawn out from a body housing, a heating chamber for confining microwave is formed by the heating container and a lid portion provided in the body housing side and covering the opening of the heating container, and electromagnetic wave leakage is prevented by providing a choke groove between an opening peripheral portion of the heating container and the lid portion facing the opening peripheral portion, so as to eliminate the electromagnetic wave leakage even if a food placing portion has a movable drawer structure (Japanese Patent Laid-Open Publication No. 11-237053 (Patent Document 3)).
There has been proposed a cooking device in which a placing portion of an object to be heated of a heating chamber has a drawable structure, comprising a cooking device body having a heating chamber, a drawer body movably disposed in the cooking device body such that the drawer body can be drawn out from the heating chamber of the cooking device body to the outside, and a slide rail for moving the drawer body in the cooking device body, wherein the slide rail is disposed outside of the heating chamber, so that it is not necessary to form the sliding mechanism with a part or a material having high heat resistance and flame resistance and it is possible to prevent the occurrence of faulty discharge by microwave (Japanese Patent Laid-Open Publication No. 2005-221081 (Patent Document 4)).
There has been proposed a slide-type cooking device, wherein a drawer body having a door and a heating container in which an object to be heated is placed therein is disposed in a cooking device body in which a heating chamber using microwave is formed therein, in a movable manner between a housed position where the heating container is housed in the heating chamber, and a drawn-out position where the heating container is drawn out from the heating chamber to the outside, and a sliding mechanism allowing the drawer body to be moved is constituted by right and left slide rails outside of the heating chamber and a center slide rail in which a drive mechanism is disposed, the respective slide rails and the drive mechanism being disposed isolatedly from the heating chamber, so that the slide rails and the drive mechanism are not exposed to a high temperature and a microwave or are not affected by food debris which could cause a breakdown (Japanese Patent Laid-Open Publication No. 2006-38296 (Patent Document 5)). Also, there has been disclosed a drawer-type food warmer having a moving rail only on the bottom face and in which the right and left side faces are opened (U.S. Pat. No. 6,849,835B2 (Patent Document 6)).
The inventions described in the above respective documents seem to have following points to be improved concerning supporting of the door. That is, in the inventions disclosed in Japanese Patent Laid-Open Publication No. 3-45820, Japanese Patent Laid-Open Publication No. 6-109257 and Japanese Patent Laid-Open Publication No. 11-237053 (Patent Documents 1 to 3), the lower side portion of the door is only butt against the bottom plate to be fixed thereto. Thus, in the case where the door is heavily loaded by body weight, a heated object or the like, an attachment portion of the door and the bottom plate could be deformed. If the attachment portion is deformed, there is a possibility that microwave for heating leaks from a gap generated between the inclined door and the body to the outside, and it is necessary to handle the apparatus with enough caution concerning the load onto the door.
In Patent Document 4, the moving mechanism is provided in right and left side walls outside of the heating chamber, and an angle member for attaching the moving mechanism is fixed to the door. Therefore, a force acting on the door is supported by the cooking device body by being relatively dispersed via the moving mechanism provided in the right and left and the center of the lower portion. When the drawer body is drawn out, the door is not inclined forward and is stably supported by the cooking device body. However, in Patent Document 4, the moving mechanism disposed in the right and left side wall faces extend through the right and left sides of the heating container when the drawer body is drawn out. Thus, when an object to be heated, for example, a heavy object such as a pot with soup therein or the like is put into or removed from the heating container which is combined with the door, the moving mechanism stands in the way, and the usability is low. Furthermore, from the standpoint of appearance, the visual quality needs to be improved. Also, Patent Document 5, in which the moving mechanism for supporting the door of the drawer body is disposed at three places of right and left side wall faces and a bottom wall face outside of the heating chamber, has the similar points to be improved as those of Patent Document 4. Furthermore, although Patent Document 6 has such a similar point with respect to the drawer structure, discloses not the cooking device, but an electric warming device, in which the drawer is only manually operated and does not have an electric moving mechanism. The electric warming device does not have an electromagnetic wave sealing mechanism or a latch hook as a safety mechanism since it is not a microwave oven. Since the drawer does not have the electric mechanism, a moving mechanism simply by a lower rail is employed.
FIG. 9 is a perspective view of a drawer-type cooking device having a conventional structure. FIG. 10 is a side view of the drawer-type cooking device shown in FIG. 9. A cooking device body 1 has a heating chamber 3 for cooking an object to be heated. A drawer body 2 is movably, namely, slidably disposed in the cooking device body 1 such that the drawer body 2 can be drawn out from the heating chamber 3 of the cooking device body 1 to the front side. The cooking device comprises a movable rail 8 formed of an angle member as a moving mechanism 4 for slidingly moving the drawer body 2 in the cooking device body 1. The drawer body 2 comprises a door 6 for opening and closing the heating chamber 3 and a heating container 7 for placing and housing an object to be heated. The heating container 7 has side walls in the right and left sides, a back wall in the back side disposed in the heating chamber 3 of the cooking device body 1, and an opening in the top, and the door 6 is attached to the front thereof. When the door 6 closes an opening of the heating chamber 3, the internal space of the heating chamber 3 becomes a sealed space by internal wall faces of the cooking device body 1 and the drawer body 2, so as to prevent microwave from leaking.
The door 6 of the drawer body 2 is supported by the cooking device body 1 by right and left side wall faces located outside of the heating chamber 3 via the moving mechanism 4. The moving mechanism 4 comprises a fixed rail 9 and the movable rail 8 sliding along the fixed rail 9. The fixed rail 9 is attached to the right and left wall faces of the heating chamber 3 outside of the heating chamber 3 of the cooking device body 1. The movable rail 8 is attached to an internal side wall face of the door 6 via a fitting 10 so as to extend from the internal side wall face of the door 6 to the inside of the cooking device body 1. Since the moving mechanism 4 for moving the drawer body 2 in the cooking device body 1 is disposed outside of the heating chamber 3, it is not necessary to use an expensive part or material having high heat resistance and flame resistance for the movable rail 8 and the fixed rail 9 which constitute the moving mechanism 4. Also, since the moving mechanism 4 is disposed outside of the heating chamber 3, a risk of discharge by microwave is eliminated without being affected by microwave emitted in the heating chamber 3.
In the known drawer-type cooking device, when the door is opened and closed by a manual operation, a large operation force is required and the operability decreases. The operability further decreases especially in the case of old people and children. In order to solve such a decrease in the operability, the drawer-type cooking device has an automatic opening and closing door driven by a motor. However, when the door in a fully closed position or in a fully opened position starts to be manually moved in the opposite direction (the fully closed door is opened or the fully opened door is closed), a large force is required.
Since it is necessary to generate a high drive force at a low speed, the moving mechanism is driven via a transmission mechanism including a reduction gear having a high reduction ratio in relation to a motor. This means that, when a rotator of the motor is seen as an object to be driven in relation to the drawer body, which is moved by a manual operation, a drive load obtained by amplifying a load by the rotator of the motor in proportion to the reduction ratio is connected to the drawer body. That is, in the case where the drawer body of the cooking device is moved by a manual operation, the rotator of the motor is to be driven via the moving mechanism, and a very high drive load in comparison with a load expected to be generated from the motor shape and the movement of the single rotator is generated. The operation force required at this time is a considerably large operation force in comparison with an operation force required in the case of a drawer-type cooking device which does not have the automatic opening and closing door driven by a motor and is manually opened and closed.
Accordingly, in a drawer-type cooking device comprising a cooking device body having a heating chamber formed therein, a drawer body having a heating container for housing an object to be heated and being drawable from the heating chamber and a door capable of closing the heating chamber, and a drive mechanism for driving the drawer body in the draw-out and push-in directions via a transmission mechanism, when the drawer body having the door starts to be manually moved in the opposite direction at a stroke end thereof, there is such a problem to be solved to at least cause the drive mechanism not to put a load during an initial period thereof.
An object of the present invention is to provide a method and device for opening and closing a door of the drawer-type cooking device, enabling to reduce the operation force by at least causing the drive mechanism not to put a load during the initial period when the door is opened or closed.
In the field of microwave oven, new distinct configuration of automatic drawer type is emerging of late, for which this invention is intended for a further improvement. This invention takes advantage of the backlash of the drawer driving mechanism; the drawer body is without the burden of the motor when the drawer is drawn within the short reign of the backlash immediately from the fully-closed position, enabling to activate the mechanism by means of a micro-switch while the drawer load stays light.